Here's a cool opportunity - Modern Sailing Academy (in Sausalito) has a few openings for their Adventure Sailing program to the Great Barrier Reef in Australia.

(image referenced from Latitude 38 magazine)

This sounds awesome. A benefit to a charter like this is that you can get your ASA Bareboat Charter certification as well as others. Check it out and let them know you heard about it at www.CharterIsland.com!